A hard disk drive (HDD) is a non-volatile data storage device which stores digitally encoded data. HDDs record data by magnetizing ferromagnetic material directionally, to represent either a 0 or a 1 binary digit. HDDs read the data back by detecting the magnetization of the material. A typical HDD design consists of a spindle which holds one or more flat circular disks called platters, onto which the data is recorded. The platters can be mounted in a stacked configuration on the spindle, which can be referred to as a platter stack. The platters are made from a non-magnetic material, usually aluminum alloy or glass, and are coated with a thin layer of magnetic material.
Information is written to a platter as the platter rotates past a read/write head that operates in close proximity with the magnetic surface. The read/write head is used to detect and modify the magnetization of the material immediately under it. Typically, there is an associated read/write head for each platter surface on the platter stack. The read/write heads can be mounted in a stacked configuration, which can be referred to as a headstack. A motor, such as a stepper motor, moves the read/write heads in an arc (roughly radially) across the platters as the platters spin, allowing each read/write head to access almost the entire surface of the platter as it spins. Control circuitry (e.g., a controller) can provide controlling signals to the headstack that controls the reading and/or writing of data by read/write heads. A cable with a flexible portion can connect the controller with the headstack.